.NET vs. Play vs. Cocoa (OS X)

.NET is a general purpose development platform. With .NET, you can use multiple languages, editors, and libraries to build native applications for web, mobile, desktop, gaming, and IoT for Windows, macOS, Linux, Android, and more.

Play Framework makes it easy to build web applications with Java & Scala. Play is based on a lightweight, stateless, web-friendly architecture. Built on Akka, Play provides predictable and minimal resource consumption (CPU, memory, threads) for highly-scalable applications.

Much of Cocoa is implemented in Objective-C, an object-oriented language that is compiled to run at incredible speed, yet employs a truly dynamic runtime making it uniquely flexible. Because Objective-C is a superset of C, it is easy to mix C and even C++ into your Cocoa applications.